In optical fiber communication networks, easily detachable connectors are widely used for connection between optical fibers. The connection is provided by butting ferrules, which are used for positioning of the optical fibers, directly against each other. Given this, in order to reduce optical loss (communication loss) from the optical fiber after the connection, a connection end face of the optical fiber connector to be connected is required to have a sufficiently smooth surface and not to generate a gap between optical fibers at the connection end faces (not to have an undercut of the optical fiber with respect to the ferrule).
Polishing of such a connection end face of an optical fiber is carried out in four steps of: removal of an adhesive; rough polishing of a spherical surface; intermediate finishing; and finish polishing. The finish polishing is carried out by pressing with a force an optical fiber connector against, while supplying water to, a surface of an abrasive film adhesively fixed onto a surface of an elastic pad.
Optical loss resulting from the finish polishing is caused primarily by end face defects such as scratches and a chipped edge due to an insufficient grinding force of the abrasive film, and decreases productivity and production cost-effectiveness of the optical fiber connector. Given this, an abrasive film used in the step of finish polishing is required to have a great grinding force.
As the abrasive film having a great grinding force, an abrasive film has been proposed that comprises an abrasive layer containing abrasive particles and a binder, in which a material for the binder is specially designed (refer for example to Japanese Unexamined Patent Application, Publication No. 2007-190613). In this conventional abrasive film, epoxy urethane, which is resistant to wear, is employed as a material for the binder to firmly fix abrasive particles in the abrasive layer, to thereby improve a grinding force.
However, in light of productivity and production cost of the optical fiber connector, the grinding force of this conventional abrasive film is not considered to be sufficient. In addition, with this conventional abrasive film, a smaller load leads to insufficient grinding force, in turn a substantial rise in a rate of defects occurring on an end face. Consequently, an end face defect is likely to occur due to variation in load conditions during polishing.